A Cal football player who collapsed in February during a training run outside Memorial Stadium died of a heart condition that has been a common cause of sudden deaths among athletes, authorities said Wednesday.

Ted Agu, 21, died of hypertrophic cardiomyopathy, or excessive thickening of the heart muscle, according to the Alameda County coroner's office. The ailment has killed many young athletes, including basketball players Hank Gathers and Reggie Lewis.

Agu, a reserve defensive lineman, collapsed during a supervised training run about 6 a.m. on Feb. 7. Team medical personnel noticed he was having a difficult time when he was about 150 yards outside the stadium.

He was put on a cart, where he was alert, but Agu collapsed when he got back to stadium. CPR started immediately and a defibrillator was used, authorities said. Emergency personnel came to the scene and transported the Cal junior to Alta Bates Medical Center in Berkeley, where he died.